Great thoughts guys. Thanks. The waiting is killing me! I bottled them at 70 degrees and it will be 2 weeks on monday. I already brewed and transfered to secondary fermentation my second batch of irish stout.... it smells soo damn good! I tried some of the beer after it sat for about 5 days just to taste how green beers taste and it still tasted amazing... flat but amazing! ill let you huys know how they turn out. Thanks for all the help and theories.

I know this has been covered before multiple times, but I can't resist...

CO2 does not "go into" the headspace and then "back into" the beer. The partial pressures of the CO2 in the beer and in the headspace are always in equilibrium. As the yeast create CO2 the pressure in the bottle increases, at that higher pressure you can have more CO2 in solution.

My guess is that what is happening is that it takes longer to create a sufficient volume of CO2 to carbonate the larger volume of beer.

CO2 does not "go into" the headspace and then "back into" the beer. The partial pressures of the CO2 in the beer and in the headspace are always in equilibrium.

Didn't I read a Revvy post about a guy who put gauges on fermenting bottles and did in fact prove that the pressure in head space did increase before the system equalized. It does seem possible that when the CO2 is initially formed that it would not go immediately into solution, but instead into the head space until it could be absorbed into the fluid.

Didn't I read a Revvy post about a guy who put gauges on fermenting bottles and did in fact prove that the pressure in head space did increase before the system equalized. It does seem possible that when the CO2 is initially formed that it would not go immediately into solution, but instead into the head space until it could be absorbed into the fluid.

I was just thinking that it may need to pressurize the head space before it's able to go into solution. Then it may reach equilibrium.?

The CO2 goes into the headspace first, no matter what size bottle you use. Once it hits a certain point, it is absorbed into the brew (put into solution)...

Personally, I would just chill one down after 3 weeks, for 4-7 days, then see where it's at. If it's carbonated fully, then you can put more in for drinking. If not, put another in to try in another 4-7 days.

Once you do enough batches, in bottles, you'll figure out how long each size will take for your brews... What works for one brewer, even with the same bottle size, might not for another...

It seems far more plausible to me that the yeast release CO2 directly into solution in the beer, and the waiting period is just the 3-4 weeks it takes to generate a sufficient volume of CO2 to carbonate the beer.

I have a very difficult time imagining a mechanism by which yeast could release CO2 and have it not be in solution. There would be minor gas exchange at the surface, the flow being from beer to headspace, to maintain equilibrium of the partial pressures.

Why would you think that the CO2 needs to come out of the beer only so it can take 3 weeks to go back in?

That being said, it might be nice to have someone actually post some real evidence, instead of listening to people like me who barely remember their college chem lectures.

I'm kegging mostly now, but when I bottle I always do a single 2L Growler along with mostly 12oz bottles and a single 22oz. The 22 is for my brother in CA so I never drink it, but I find the the growlers seem to condition and carbonate faster than a 12oz does.

I propose an experiment. I need a beer to do it on though... Maybe my IPA? It needs something done to it.

Deepest respect and appreciation for Revvy and AnOldUR. I was ready to disagreee with some of their information on this post (I should Know better), but their explanations about exposed surface area make absolute sense. Many books/instructions suggest 2 weeks for bottle carbing, and carbonation can be accomplished in this time, but Revvy's 3 weeks minimum has definitely resulted in more pleasurable consumption. Thank you sincerely!

On my first batch I filled numerous 22oz bombers. The last one I bottled didn't fill up all the way because I ran out of beer. It reached to just below the neck leaving more surface area and a lot more head space. I drank it after 3 weeks and it actually had more carbonation than the ones filled all the way up. That surprised me and lends credence to the surface area theory.